== Why is this an issue? If you only want one instance that matches certain criteria out of a collection, it's far more efficient to grab the first matching item than it is to fully filter the collection for your criteria and then only use a single value. === Noncompliant code example [source,swift] ---- let one = arr.filter { $0.containsString("yo") }.first // Noncompliant ---- === Compliant solution [source,swift] ---- let one = arr.first(where: { $0.containsString("yo") }) ---- ifdef::env-github,rspecator-view[] ''' == Implementation Specification (visible only on this page) === Message Convert this "filter...first" operation to "first(where: ...)". === Highlighting primary: ``++first++`` secondary: ``++filter++`` endif::env-github,rspecator-view[]